Process for the preparation of cyclopentadienyl manganese compounds



PROCESS FOR THE PREPARATION OF CYCLO- PENTADIENYL MANGANESE COMPOUNDS Earl G. De Witt, Royal Oak, and Jerome E. Brown, De-' troit, Mich., and Hymin Shapiro, East Baton Rouge, La., assignors to Ethyl Corporation, New York, N. a corporation of Delaware No Drawing. Filed Jan. 27, 1958, Ser. No. 711,183

4 (Ilaims. (Cl. 260-429) This invention relates to novel hydrocarbon manganese compounds and to a process for their preparation.

Attendant with the development and evolution of the internal combustion engine for passenger car and heavyduty service, the petroleum industry has been continually called upon to effect improvements in the antiknock quality of hydrocarbon fuels. These improvements have, in general, been brought about by two distinct methods. One of these methods comprises improvements in refining operations such as thermal and catalytic cracking and reforming or alkylating processes. The other method comprises the use of fuel additives to effect an increase in the antiknock qualities of the hydrocarbon fuels. Inasmuch as improvements in refinery techniques involve considerable capital expenditures, the use of fuel additives has attained greater and more widespread acceptance as the more effective method, particularly from the economic standpoint. The instant invention is therefore concerned with providing novel hydrocarbon manganese compounds useful as additives to fuel and lubricating oils and also useful in the synthesis of other manganese compounds which are capable of improving combustion characteristics of hydrocarbon fuels and as additives to lubricating oils and greases, and the like.

It is therefore an object of our invention to provide novel hydrocarbon manganese compounds. It is also an object of this invention to provide hydrocarbon manganese compounds which are useful as additives for liquid and solid combustion fuels, and lubricating oils and greases, as ,well as for other uses. It is likewise an object to provide a process for the preparation ,of novel hydrocarbon manganese compounds. Additional important objects of this invention will become apparent from the discussion which follows.

The objectives of this invention are accomplished by a process which comprises reacting an alkali metal cyclomatic hydrocarbon compound having from 5 to about 17 carbon atoms and which embodies a group of 5 carbons having the general configuration found in cyclopentadiene with a manganese salt, and subsequently recovering a thermally stable cyclopentadienyl manganese compound. By a thermally stable cyclopentadienyl manganese compound is meant a compound which when heated in an inert atmosphere, does not decompose at temperatures below about 200 C.

An embodiment of this invention comprises a process for the preparation of a bis(cyclomatic)manganese compound which comprises reacting a manganese salt with an alkali metal cyclomatic hydrocarbon compound, as defined above aTnd cyclopentadiene. The reaction is preferably carried out in the presence of a suitable, prefer ably non-aqueous, solvent, examples of which are hydrocarbons such as benzene, cyclohexane, diisobutylene, toluene; and ethers, such as diethyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, propylene glycol methylphenyl ether, methylphenyl ether, tetrahydrofuran, dioxane, dodecyl ether, etc. In other words,

United States Patent 0 having the general configuration found in cyclopentahydrocarbon and'ether solvents having up to about 20 carbon atoms may be employed.

The products of this embodiment of the invention are:

hydrocarbon cyclomatic manganese compounds wherein R and Rcan be the same or different and are cyclomatic hydrocarbon radicals having from 5 to about 17 carbon atoms which embody a group of 5 carbons diene, said compound being further characterized in that the cyclomatic hydrocarbon radical is bonded to the manganese through the carbons comprising the cyclopentadienyl-group configuration. Any substituents attached to the cyclopentadienyl group in the radical can However, radihave from 1 to about 12 carbon atoms. cals in which the substituents have from 1 to about 20 or more carbon atoms are also applicable to the process of this invention. 7

Another and preferred embodiment of this present invention is a process which comprises reacting an alkali metal cyclomatic hydrocarbon compound as defined above with a manganese salt, then reacting the bis(cyclomatic)manganese compound thus prepared with carbon monoxide and subsequently separating a thermally stable cyclomatic manganese tricarbonyl compound. This embodiment of the invention is preferred as it leads to products which are highly useful as antiknock additives to gasoline for use in spark ignition internal combustion engines. operations wherein the final stages of product recovery are conducted in a continuous fashion. Solvents profitably employed in this embodiment of the invention include cyclic ethers such as dioxan and tetrahydrofuran and the lower alkylene ethers of ethylene glycol and di-. ethylene glycol such as ethylene glycol diethylether and the dimethylether of diethylene glycol.

The cyclomatic groups of the compounds of the presentinvention can be represented by four general formulae as follows:

R; R, R3 in wherein each of 11 ,11 R3, 12,, R5, R6, 11,, R8, and R,

can bethe" same. or different and is selected from the group consisting of hydrogen and organic and hydrocar bonradicals having from 1 to about 12 ormore carbon O atoms, and whereina and b can be the same orditferenl;

It is furthermore highly adapted to commercial and are small whole integers including and excluding l, the sum a+b being at least 2.

Non-limiting examples of the compounds of this invention in which the cyclomatic radical has theconfiguration shown in structure I above are bis(1,2 dipropyl 3-cyclohexylcyclopentadienyl)manganese; bis(tolylcyclopentadienyl)manganese; bis(l,3-diphenylcyclopentadienyl)manganese; bis(acetylcyclopentadienyl)manganese; cyclopentadienyl (methylcyclopentadienyl) manganese; cyclopentadienyl (idenyl)manganese,

and the like, including ethyl cyclopentadienyl manganese tricarbonyl.

When there is only one organo or hydrocarbon substituent on the cyclopentadienyl ring, its position is not specified since, according to theory, the cyclopentadienyl ring or group is bonded to the manganese by five equivalent bonds running from each of the five carbons in the cyclopentadienyl ring to the manganese. Since all these bonds are equivalent and all five carbons in the ring are equidistant from the manganese, it is immaterial to which of the five carbons a single substituent is attached. When, however, more than one substituent is attached to the cyclopentadienyl ring, the positions are given so as to indicate the relative positions of the difierent substituents with respect to each other on the cyclopentadienyl ring.

Examples of compounds having the configuration of structure 1! given hereinabove are bis(indenyl)manganese; bis(3 methylindenyl)manganese; bis(3 ethylindenyl)manganese; bis(2,3 dimethylindenyl)manganese; bis( 1,3 diethylindenyl)rnanganese; bis(l,7-diisopropylindenyl) manganese; bis l ,2,3,4,5,6,7-l1eptamethylindenyl) manganese; 5 phenylindenyl(3(2-ethylphenyl)indenyl)- manganese, indenyl manganese tricarbonyl, etc.

Examples of compounds having the configuration of structure III above are bis(fiuorenyl)manganese; bis(3- ethylfiuorenyl)manganese; bis(4 propylfiuorenyDmanganese; bis(2,3,4,7-tetramethylfluorenyl)manganese, and the like.

Examples of compounds having the configuration of structure IV above are bis(4,5,6,7-tetrahydroindenyl)- manganese; bis(3-methyl-4,7-dihydroindenyl)manganese; bis(2 ethyl 3-phenyl-4,5,6,7-tetrahydroindenyl)manganese; bis(1,2,3,4,5,6,7,8 octahydrofiuorenyl)manganese; bis( l,4,5,8-tetrahydrofluorenyl)manganese, and the like.

The manganese salts employed in the process of this invention are salts of organic or inorganic acids, preferably the respective manganous salts. Examples of these manganese salts are manganous acetate, manganous benzoate, manganous carbonate, manganous oxalate, manganous lactate, manganous nitrate, manganous phosphate, manganous sulfate, manganic phosphate, manganous fluoride, manganous chloride, manganous bromide, manganous iodide, and the like. In addition, manganese salts of fi-diketones, such as tris(2,4-pentanedione)manganese and tris(2,4-hexanedione)manganese may also be employed; as well'as manganese salts of B-keto esters, such as the manganese salts of ethylacetoacetate, and the like.

cyclopentadienyl sodium with manganous halide to give bis(cyclopentadienyl)manganese. Cyclomatic alkali metal compounds are also reacted with naturally occurring manganese ores, such as manganosite (MnO), manganese dioxide (MnO manganic sesquioxide (Mn O manganous sulfide (MnS), manganic sulfide (MnS rhodochrosite (MnCO and the like, to give bis(cyclomatic)manganese compounds such as bis(methylcyclopentadienyl)manganese, etc.

The cyclomatic alkali metal compound used in the preparation of our compounds can be prepared by the reaction of a cyclomatic compound with an alkali metal directly, or with an alkali metal compound. Thus, a cyclomatic alkali metal compound can be prepared by reacting a cyclomatic compound with an alkali metal derivative of a compound which is less acidic than the cyclomatic compound. The process is carried out in an inert atmosphere, such as nitrogen, argon, helium, methane, etc., to prevent oxidation due to oxygen in the air. For example, cyclopentadienyl sodium can be prepared by reacting cyclopentadiene with a sodium alcoholate such as sodium methylate, sodium ethylate, sodium benzoate, etc. Potassium, rubidium and cesium can be used in place of sodium.

The cyclomatic alkali metal compounds can also be prepared by reacting hydrocarbon cyclomatic compounds containing the cyclopentadienyl group with alkali metal derivatives of amines, such as sodamide, and the alkali metal derivatives of alkyl and aryl hydrocarbon amines in which not more than two of the hydrogens in ammonia are substituted by alkyl and/or aryl hydrocarbon groups as, for example, sodioanilide, potassium ethyl amide, rubidium diisopropyl amide, cesium methylethyl amide, etc.; alkali metal aryl methanes, such as benzyl sodium, di(pheny1)methyl potassium, tri(2,4 dimethylphenyl)- methyl rubidium, alkali metal arylalkyl methanes, such as sodiocumene, 5(a-naphthyl)decyl potassium, etc.; alkali metal acetylides, such as sodioacetylide, potassium acetylide, etc., and the like.

The cyclomatic manganese product can be separated from the reaction mixture by solution in a solvent, such as ether, and the removal of the solid impurities by filtration, centrifugation, and the like. The product can also be separated from the reaction mixture by vacuum distillation or selective solvent extraction. The solvent may be removed from the product by fractional distillation and the product further purified by fractional distillation or sublimation. The method of preparation is further illustrated in the examples below.

EXAMPLE I Bis(cycl0pentadienyl) manganese A reaction vessel equipped with means for charging and discharging liquids and solids, gas inlet and outlet means, temperature measuring devices, heating and coolingmeans, means for agitation. and means for condensing vapors, was flushed with prepun'fied nitrogen. To the flask were then added 400 parts of tetrahydrofuran and 23 parts of sodium dispersed in 23 parts of mineral oil. An atmosphere of nitrogen was maintained in the reaction vessel throughout the run. The vessel was cooled to 10 C. and 66.7 parts of freshly-distilled cyclopentadiene was added in small increments with agitation while maintaining the temperature below 15 C. After the addition of the cyclopentadiene, the temperature was allowed to rise to 23 C. over a period of about two hours, when the completion of the formation of the sodium cyclopentadiene was evidenced by the cessation of hydrogen evolution. To this solution of cyclopentadienyl sodium in tetrahydrofuran was added 63 parts of anhydrous manganous chloride. The mixture was heated andmaintained at reflux temperature for 20 hours. At the end of this time, the solvent was removed by distillation under reduced pressure and the product purified by An example of the process employed in the reaction'of sublimation at a pressure of about 2 mm. of mercury at about 130 C., producing 48.64 parts, 52.3% yield, of lustrous, brown-black bis(cyclopentadienyl)manganese crystals. Analysis of the product showed it to contain 64.9 percent carbon and 5.44 percent hydrogen, corresponding to the formula (C H Mn; calculated 64.9 percent carbon and 5.41 percent hydrogen. The bis- (cyclopentadienyl)manganese oxidizes readily in air and should therefore be kept in an inert atmosphere, such as nitrogen.

EXAMPLE II Bis(methylcyclopentaa'ienyl manganese The procedure of Example I was followed employing 400 parts of tetrahydrofuran, 23 parts of sodium dispersed in 23 parts of mineral oil, 80 parts of freshlydistilled methylcyclopentadiene, and 63 parts of powdered MnCl containing 3.11 percent water. The manganous chloride was added to the methylcyclopentadienyl sodium solution at a temperature of 20 C. After maintaining the mixture at reflux temperature for two hours, the compound bis(methylcyclopentadienyl)manganese was separated by distillation at reduced pressure under nitrogen. It was a viscous, reddish-brown liquid which crystallized on standing. Analysis showed it to contain 66.7 percent carbon and 6.54 percent hydrogen, corresponding to the formula (C H Mn; calculated 67.6 percent carbon and 6.62 percent hydrogen. The yield was 84.3 percent based on the amount of MnCl em ployed. The bis(methylcyclopentadienyl)manganese is spontaneously combustible and therefore should not be exposed to oxygen of the atmosphere. The compound is stable to thermal decomposition at temperatures above 200 C. This is evidenced by the fact that when the compound was heated at 225 C. for two hours under pressure of neon essentially no decomposition of the bis(cyclopentadienyl)manganese occurred.

A variation of Example II, by which the same product is prepared, consists of adding methylcyclopentadiene to a mixture of manganous chloride and sodium dispersed in mineral oil.

EXAMPLE III Bis(ethyleyclopentadienyl) manganese Ethylcyclopentadiene was prepared by reaction of cyclopentadienyl sodium with ethyl bromide in tetrahydrofuran. Then, bis(ethylcyclopentadienyl)manganese was prepared according to the process described in Example I.

EXAMPLE IV Bis(allylcyclopentadienyl) manganese The procedure of Example III is followed by using allyl chloride in place of ethyl bromide, potassium in place of sodium, and tris(2,4-pentanedione)manganese in place of manganous chloride. A good yield of bis- (allylcyclopentadienyl)manganese is obtained. Good yields are also obtained when lithium is used in place of potassium.

EXAMPLE V Bis(phenylcyclopentadienyl) manganese 6 EXAMPLE v11 Bis( indenyl manganese The procedure of Example I was followed using indene in place of cyclopentadiene. After addition of anhydrous; manganous chloride to the indenyl sodium in tetrahydro} furan, the reaction mixture was refluxed for three hours.

Separation of product according to Example I produced r a good yield of bis(indenyl)manganese which, on analysis,

was found to correspond to the formula (C H Mn.

EXAMPLE VIII Bis(] ,2,3,4,5-pentamethylcyelopentadienyl)manganese The procedure of Example II is employed using 136 parts of 1,2,3,4,5-pentamethylcyclopentadiene and 108 parts of manganous bromide (MnBr Lithium is used in place of sodium. A good yield of bis(1,2,3,4,5-pentamethylcyclopentadienyl)manganese is obtained EXAMPLE IX Bis( octy leyclopentadienyl) manganese EXAMPLE X Bis(]-naphthyl-Z-ethylcyclopentadienyl)manganese The procedure of Example II is followed using 222 parts of 1-naphthyl-Z-ethylcyclopentadiene and 63 parts of manganous fluoride. The reaction mixture upon sepa ration treatment produced bis(l-naphthyl-Z-ethylcyclopentadienyl)manganese in good yield.

EXAMPLE XI Bis(1,3,4,5-tetramethylindenyl)manganese The procedure of Example II is carried out employing 172 parts of 1,3,4,7-tetramethylindene and 86 parts Bis 1,3,4,7-tetramethy1indenyl)-I of manganous acetate.

manganese is separated in good yield from the reaction product. EXAMPLE XII Bis(3-cycl0hexylindenyl) manganese Following the procedure of Example II, 192 parts of 3-cyclohexylindene is reacted with 150 parts of nianga-; i nous benzoate and bis(3-cyclohexylindenyl)manganese is obtained in good yield. I

EXAMPLE XIII Bis(4,5,6,7Jetrahydroindenyl) manganese According to the process of Example II parts of 4,5,6,7-tetrahydroindene is reacted with 72 parts of manganous oxalate. hydroindenyl)manganese is obtained.

EXAMPLE XIV Bis(1,2,3,4,5,6,7,8-0ctahydr0flu0renyl) manganese A The procedure of Example II is followed in reacting 174 parts of 1,2,3,4,5,6,7,8-octahydrofluorene with 76 parts of manganous sulfate and bis(1,2,3,4,5,6,7,8 octa' hydrofluorenyl)manganese is obtained.

EXAMPLE XV Bis(],8-dzethylfluorenyl)manganese 7 Following the procedure described in Example II, 222

parts of 1,8-diethylfluorene is reacted with 93, parts ofr i manganous nitrate and bis(1,8-diethylfluorenyl)mangak.

nese is obtained.

A good yield of bis(4,5,6,7 -tetra- 7 EXAMPLE XVI Bis(flurenyl) manganese The procedure of Example II is followed in reacting 166parts of fluorene with 59 parts of manganous phosphate, and bis(fluorenyl)manganese is obtained.

EXAMPLE XVII Bis(methyIcyclapentadienyD'manganese Following the procedure of Example l, 80 parts of methylcyclopentadiene were slowly added to 39 parts of sodamide in 250 parts of tetrahydrofuran. The mixture was heated to, and held at, reflux temperature for a period oftwo hours. It was then cooled to 12 C. and 63 parts of MnCl were added. Heat was then applied and the mixture kept at reflux temperature for a period of about 16 hours. A good yield of bis(methylcyclopentadienyl)- manganese was separated from the reaction mixture.

The temperatures of the steps in our process may be varied. For example, the reaction of the alkali metal with the cyclomatic compound can be performed at temperatures up to the boiling point of the cyclomatic com pound. For dicyclopentadiene, this is about 175 C. at which point cracking of the monomer occurs, and the latter reacts with sodium to form cyclopentadienyl sodium. A preferred range of temperatures is from about C. to about 65 C. when conducting the reaction in a solvent, such as tetrahydrofuran. The upper temperature represents the boiling point of tetrahydrofuran. The manganese salt, i.e., MnCl MnBr or MnSO etc., may be added to the alkali metal cyclomatic compound at temperatures ranging from 20 to 65 C. and higher, depending on the boiling point of the solvent, and since there is no great temperature rise upon addition of the manganese halide, the temperature limits are not critical. However, we prefer to conduct this reaction at a temperature of from 20 to 65 C. in order to cut down the time of reaction. The reaction mixture need not be refluxed, however, reflux periods up to 16 hours have been employed with good success.

The time of reaction of any part of the processes depends on temperature and will vary over a wide range. For instance, the reaction of sodium with cyclopentadiene is practically instantaneous and the rate of admixture of reactants depends on the efiiciency of cooling. Therefore, the time of reaction can vary from several minutes to a few hours, such as four hours.

Solvents other than tetrahydrofuran, ether, and benzene were used in other runs which are not included in the illustrative examples given hereinabove. Such other solvents, or mixtures thereof, which were employed are n-butyl ether, dioxane, toluene, and dimethyl ether of ethylene glycol.

The alkali metals used in our process to make the metal derivatives of the cyclomatic compounds which are then reactedwith a manganese metal or compound to make the cyclomatic manganese compound include lithium, sodium, potassium, rubidium, and cesium. Metals other than the alkali metals that can be used are the group IIA metals, such as beryllium, magnesium, calcium, strontium, and barium, and group IIB metals such as zinc and cadmium. In the case of polyvalent metals, the compounds may contain halogen such as the Grignard reagent in the case of magnesium.

In the above examples, nitrogen was employed as the inert atmosphere to prevent oxygen from coming in contact with the reactants. Other inert gases are also used, e.g., argon, methane, ethane, propane, and other hydrocarbons and vapors of the solvents employed in the reaction.

Our compounds are useful in the synthesis of other manganese compounds which are capable of improving combustion characteristics of hydrocarbon fuels as stated hereinabove. An example of such use is the preparation ofmethylcyclopentadienyl manganese tricarbonyl as described in-the following example.

EXAMPLE XVIII Methylcyclopentadienyl manganese tricarbonyl Bis(methylcyclopentadienyl)manganese, prepared as described in Example II, was added to the pressure resistant vessel under a nitrogen atmosphere and the vessel charged with carbon monoxide. The vessel and contents were then heated from 22 C. to about 148 C. while maintaining the pressure in the reaction vessel within the range of from about 680 to 2175 p.s.i. The uptake of carbon monoxide ceased in about one hour indicating. the completion of the reaction, whereupon the vessel was cooled and methylcyclopentadienyl manganese tricarbonyl separated from the reaction mixture. The methylcyclopentadienyl manganese tricarbonyl is stable to thermal decomposition at elevated temperatures in excess of 200 C. This was demonstrated by determining the rate of decomposition at 240 C. under vacuum. The rate of thermal decomposition was found to be 0.2'percent per hour.

EXAMPLE XIX Methylcyclopentadiene dimer is gradually added to sodium metal (1526 parts) in diethylene glycol dimethyl ether (4560 parts) in a reactor provided with heating meansand means to agitate the mixture. The solvent was previously used in other similar reactions. The total feed of methylcyclopentadiene over a two hour period was 6060 parts. The reaction was continued for minutes at 190 C. under a total pressure of 25 lbs. The reaction mixture was stirred during the entire reaction. Hydrogen gas was evolved and recovered from the reactor. Thereafter, 4310 parts of flake-d, anhydrous manganous chloride (97 percent pure) was added to the reaction mixture and the reaction was maintained at a temperature of until the reaction had ceased. This is determined by measuring the apparent pH (from 8 to 8.5 being taken as the end point). The reaction mixture was also agitated during this reaction. The reaction mixture was then transferred to a pressure vessel provided with an agitator and to this reaction mixture was added carbon monoxide at a pressure of 350 p.s.i.g. The total carbon monoxide consumed in the reaction was 2550 parts. The reaction was maintained at a temperature of 193 C.

The crude reaction mixture was then discharged to a vacuum distillation still and the volatile components removed by distillation at a pressure of about 50 millimeters of mercury. The overhead temperature at the end of this vacuum distillation was about C. Before the distillation was started, 5750 parts of a high boiling hydrocarbon mixture which is predominantly alkylated naphthalene derivatives sold under the trade name Phillips Aromatic Petroleum Fraction having an IBP of 330 C. and an average molecular weight of 246, was added to the still. The vacuum distillation was continued until no volatile materials were left in the residue. The volatile components from this and other runs were collected and were then subjected to fractionation in a 30 plate column on a continuous basis. The fractionation was continued at atmospheric boiling temperature and the crude material was injected into the column on the fifteenth plate. The solvent and cyclopentadiene (monomer) were removed overhead and recycled to the sodium reactor for the second cycle. The monomer was fed directly to the sodium reaction. However, in other runs, it is first dimerized by heating for several hours at 120 C. This results in a less vigorous reaction with sodium. The total methylcyclopentadienyl manganese tricarbonyl in the solvent cyclopentadiene mixture was less than 0.001 parts per part of sodium. The above process was repeated and the yields obtained in this and subsequent cycles were essentially identical to the yields obtained in the first cycle in which fresh solvent was employed. It is found that about 95 percent or more of the ether solvent is recovered in this process and only minor quantities of fresh solvent are required to make up a solvent loss in the process. In second and subsequent cycles it is important that the concentration of methylcyclopentadienyl manganese tricarbonyl present in the sodium reaction be kept as low as possible, since its presence at this point reduces the ultimate yield.

This compound, as well as other cyclomatic manganese tricarbonyl compounds, is found to be an exceptionally good agent for improving the antiknock quality of hydro carbon fuels used in spark ignition engines. For example, when methylcyclopentadienyl manganese tricarbonyl was added to a commercial gasoline having an initial boiling point of 94 F. and a final boiling point of 390 F. in amount sufficient to prepare a composition containing 1 gram of manganese per gallon, the octane number of the gasoline was raised from 83.1 to 92.3 as determined by the Research Method. The Research Method of determining the octane number of a fuel is generally accepted as a method of test which gives a good indication of fuel behavior in full-scale, automotive engines under normal driving conditions and the method most used by commercial installations in determining the value of a gasoline or additive. The Research Method of testing antiknocks is conducted in a single-cylinder engine especially designed for this purpose and referred to as the CFR engine. This engine has a variable compression ratio and during the test the temperature of the jacket water is maintained at 212 F. and the inlet air temperature is controlled at 125 F. The engine is operated at a-speed of 600 rpm. with a spark advance of 13 before top dead center. The test method employed is more fully described in test pro cedure D-908-5 5 contained in the 1956 edition of ASTM Manual of Engine Test Methods for Rating Fuels.

The importance of the thermal stability of the cyclopentadienyl manganese compounds produced by the process of this invention can be appreciated by consideration of the use to which these compounds are put. In the preparation 'of a cyclopentadienyl manganese tricarbonyl compound wherein a bis(cyclopentadienyl)manganese compound is employed as an intermediate the best yields are obtained at elevated temperatures. Were the bis- (cylcopentadienyl)manganese compound not stable at these temperatures, little or no cyclopentadienyl manganese tricarbonyl would result from the reaction and it would be necessary to conduct the reaction at lower temperatures at which the intermediate was stable with the consequent drastic reduction in yield. With respect to "the cyclopentadienyl manganese tricarbonyl compounds,

it is to be noted that thermal stability is an important factor in the employment of such compounds as antiknock agents. Any compound not having the requisite thermal stability, would be inapplicable for use as a fuel additive since high temperatures are often encountered in the storage of fuel and in the intake manifold of the engines in which such fuels are used. Furthermore, the reaction temperatures and isolation conditions employed by virtue of the boiling point of the compounds requires that they be stable at the elevated temperatures. Thus, if the compounds were not thermally stable, their utility would be seriously impaired, or in the extreme case, it would be impossible to utilize them as fuel additives.

The cyclomatic compounds of the present invention possess particular utility as additives. Thus, many of the cyclomatic derivatives can be used as fuel additives, such as for fuels for internal combustion engines of both the spark ignition and compression ignition types, fuels for jet engines and rockets fuels, and the like. Likewise, many of the cyclomatic compounds of the present inven tion can be successfully employed as additives to natural and synthetic lubricants as well as the more viscous uncgreases. Y

Other important uses of the cyclomatic compounds of the present invention include the use thereof as chemical intermediates, particularly in the preparation of metal and metalloid containing polymeric materials. In addition, some of the cyclomatic derivatives of this invention can be used in the manufacture of medicinals and other therapeutic materials 'as well as agricultural chemicals such as, for example, fungicides, insecticides, defoliants, growth regulants, and so on.

A particular advantage of the new compositions of matter of the present invention is the fact that by proper selection of the cyclomatic groups attached to the manganese, compounds having tailormade characteristics can be obtained. For example, compounds such as bis(cyclopentadienyl)manganese, cyclopen-tadienyl indenyl manganese, methylcyclopentadienyl indenyl manganese, bis(indenyl)manganese, will possess different degrees of stability, volatility, and solubility due to the varying complexity of the cyclomatic groups in the molecule. Likewise, the selection of the cyclomatic constituents enables the preparation of compounds of diverse applicability.

This application is a continuation-in-part of our earlier filed applications Ser. No. 297,392, filed July 5, 1952, Ser. No. 527,124, filed August 8, 1955 (now U.S. Patent No. 2,839,552), SerfNo. 417,920, filed March 22, 1954, and Ser. No. 666,743, filed July 19, 1957 (now U.S. Patent 1 Io. 2,898,354); said last-identified application being a division of application Ser. No. 521,364 (now U.S. Patent No. 2,818,417) which in turn is a continuation-inpart of application Ser. No. 325,224, filed December 10, 1952 (now U.S. Patent No. 2,818,416).

Having fully described the novel cyclomatic derivatives of the present invention, the need therefor, and the best methods devised for their preparation, we do not intend that our invention be limited except within the spirit and scope of the appended claims.

We claim:

1. process for the preparation of a hydrocarbon cyclomatic manganese compound having the general formula wherein R and R are cyclomatic hydrocarbon radicals having from 5 to about 17 carbon atoms which embody a group of 5 carbons having the general configuration found in cyclopentadiene, said compound being further characterized in that the cyclomatic hydrocarbon radicals are bonded to the manganese through the carbons comprising the cyclopentadienyl-group configuration, which process comprises reacting a manganese salt, consisting of manganese bonded to a negative radical, with an alkali metal cyclomatic hydrocarbon compound having from 5 to about 17 carbon atoms which embodies a group of 5 carbons having the general configuration found in cyclopentadiene and in which the alkali metal is bonded to a carbon of said 5 carbons comprising the cyclopentadienyl group. I

2. A process which comprises reacting an alkali metal cyclomatic hydrocarbon compound having from 5 to about 17 atoms and which embodies a group of 5 carbons having the general configuration found in cyclopentadiene and in which said alkali metal is bonded to a carbon of said 5 carbons with a manganese salt, consisting of manganese bonded to a negative radical, and subsequently recovering a thermally stable cyclopentadienyl manganese compound having the general formula RMnR wherein R and R are cyclomatic hydrocarbon radicals having from 5 to about 17 carbon atoms which uration found in cyclopentadienc.

11' 3. Thetprocesszof claim 1 wherein said manganese salt is a manganous halide.

4. The process of claim 1 wherein said manganese salt is manganous chloride.

References Cited in thefile of this patent UNITED STATES PATENTS 12 FOREIGN PATENTS Great Britain Sept: 11, 1957 OTHER REFERENCES Wilkinson et a1: Chemistry and Industry, pages 307- 308, March 13, 1954.

King et al.: Fundamentals of College Chemistry, 2nd edition, 1954, published by American Book Co., page 17 relied on. 

1. A PROCESS FOR THE PREPARATION OF A HYDROCARBON CYCLOMATIC MANGANESE COMPOUND HAVING THE GENERAL FORMULA 